RBSE Class 8 Science Chapter 12 Artificial Satellite Solutions

In RBSE Class 8 Science Chapter 12 Artificial Satellite, students learn about man-made objects such as satellites, which observe the movement of planets in the solar system. Here, we bring you the important questions and solutions of the chapter that will aid students to understand and prepare for all important topics listed in this chapter and excel it.

Here’s a modest attempt from our end to cover the explanations of important questions of RBSE Class 8 Science according to different chapters. We hope that students can benefit from these solutions and explore various new concepts and benefit from it while preparing for the RBSE Class 8 2020 exam.

We have solved the important textbook questions and added a few additional questions with solutions of the RBSE Class 8 Science textbook for Chapter 12 Artificial Satellite from the RBSE Class 8 Science Syllabus. Students can practice from these questions to have a sound knowledge of the chapter and can also revise from these solutions just before their exams and score good grades in this section.

Question 6: The first Indian artificial satellite ____________________ was launched on April 19, 1975.

Answer: Aryabhatt

Short Answer Type Textbook Questions

Question 1: Explain the difference between the artificial satellite and natural satellite.

Answer: Man-made objects revolving in certain orbits around the planet Earth or other planets are known as artificial satellites. On the other hand, natural satellites are those natural objects which orbit around our planet Earth or other planets. For instance, the moon is considered the natural satellite of planet Earth.

Question 2:The objects, which are thrown upwards from the Earth, and return back to Earth whereas an artificial satellite does not return back. Why?

Answer: Due to the gravitational force of Earth, all the objects thrown up return back to Earth while an artificial satellite has a velocity, which is little less than the escape velocity of 11.2 km/sec. Since it doesn’t cross the Earth’s gravitational attraction, it starts revolving in a certain orbit around the Earth.

Question 3: Differentiate between geo-stationary satellite and polar satellite on the basis of orbital motion, distance from Earth and its uses.

Answer: Here are the differences between geo-stationary satellite and polar satellite:

Properties

Geo-stationary satellites

Polar Satellites

1. Orbit

These satellites revolve in equatorial linear orbits and

complete one rotation around Earth in 24 hours

These satellites revolve in polar orbits of the Earth

and comparatively take less time to complete one rotation around Earth

2. Distance from Earth’s surface

These satellites are positioned at 36000 km upward distance from

the Earth’s surface

These satellites are positioned at 500 to 800 km from the Earth’s surface

3. Purpose/Uses

Such satellites are used for telecommunication purposes

Such satellites are used for remote sensing, environmental study and weather science, etc.

Long Answer Type Textbook Questions

Question 4: What do you mean by artificial satellite? Write its uses.

Answer: Man-made satellites which revolve around Earth and other planets are known as artificial satellites. These are different from natural satellites. Artificial satellites are sent into space by rocket or some satellite launching vehicle.

Uses of artificial satellites: Some of the uses of artificial satellites include:

1. It is used for telecommunication purposes through telephone, television, mobile phones, internet services, etc. where we receive signals from different locations across the globe and transmit it to other parts of the world.

2. It is used to secure important information about geological and meteorological areas.

3. It helps in estimating the crop area and production.

4. It helps scientists to stay updated about droughts and food production and to estimate the loss from these calamities.

5. Artificial satellites help in discovering underground water reserves and contribute to water management.

6. Artificial satellites are used for identifying the mineral in geological repositories.

7. It assists forest conservation by surveying and maintaining the forest areas.

8. It helps to monitor the sea ports, airports, defence posts etc. This helps to preserve the security management easily.

9. Artificial satellites help to spy and in monitoring of army activities.

10. It helps to get information about the events happening around the atmosphere and space.

11. Helps in identifying the exact location of an aeroplane, a ship, a person, and an object.

Question 5: Write down any five Indian satellite’s names, launching year and their uses.

Answer: Given below are the five Indian satellite’s names, launching year and their uses:

Answer: Types of artificial satellites: Artificial satellites are classified into two categories, based upon the distance from the Earth’s surface:

(i) Geo-stationary Satellite: Every satellite revolves on a fixed path around the Earth known as the orbit. A satellite usually moves around the Earth but when it is seen from the Earth it appears stationary and is known as a Geo-stationary Satellite. This satellite is located at 36000 km. approx. from the Earth’s surface. A Geo-stationary Satellite revolves in an equatorial linear orbit. The revolutionary time period of Geo-stationary satellites is 24 hours which is equal to the rotational period of planet Earth. These satellites are used in satellite telephones, televisions, radios, etc. for communication across the globe. For this reason, Geo-stationary Satellites are also known as telecommunication satellites.

(ii) Polar Satellite: Those satellites which revolve in polar orbits of planet Earth are known as Polar Satellites. In comparison to Geo-stationary Satellites, Polar Satellites revolve at a lesser height from the surface of the earth which is 500-800 km approximately. These satellites mainly furnish information about the atmosphere like – clouds pictures, hole in the Ozone layer, etc. The information collected from these satellites are being extensively used for remote sensing and environment study, etc. India has launched many remote sensing satellites such as IRS – IA, IRS-2B, IRS-3C etc. for transmitting signals on radio, TV and mobiles.

Question 7: Write an essay on contribution of Indian Space Research Organisation in Indian space programme.

Answer: In 1962, the Indian National Committee for Space Research (INCOSPAR) was called by the Department of Atomic Energy, which was led by popular scientist Homi Jahangir Bhabha. It was re-established or renamed in 1969 as ISRO (Indian Space Research Organization). In India, manufacturing, development and launching of satellites are done by ISRO. Dr. Vikram Ambalal Sarabhai was known to have started the Indian space programme. All space and planetary related research and development works are being extensively carried out on the basis of space-related experiments done by ISRO. Dr. A.P.J. Abdul Kalam played a vital role in designing and manufacturing the satellite launching vehicle in India while working on many major projects of ISRO.

Nowadays, India has become self-reliant in manufacturing of the high standard satellite launching vehicle. Many countries like America and others also use Indian satellite launching vehicles to launch their artificial satellite into space. More than 50 satellites have been launched by ISRO for other countries. ISRO’s centres are spread across Pan-India. Its main launching centre is at Sriharikota (SHAR) at Chennai. Vikram Sarabhai Space Centre is located at Thiruvananthapuram and the National Centre for space related research is Physical Research Laboratory at Ahmedabad (PRL). At Jodhpur, Rajasthan a remote sensing centre is located which studies the obtained maps, information and other data, etc. from artificial satellites.

Additional Short Answer Type Questions

Question 1: When and where was the first Indian artificial satellite launched into space? Explain the purpose.

Answer: The first Indian artificial satellite that was launched into space on 19th April, 1975 was called “Aryabhatt” which was named after the famous ancient Indian mathematician, Aryabhatta. It was launched through Baikonur Space Station of the European Union, The main purpose of this satellite was to study the Earth’s atmosphere.

Question 2: When did India start launching polar satellites? What was the purpose?

Answer: Towards the end of 1980, India started launching polar satellites into space, which were known as Indian remote sensing satellites i.e, IRS series satellites. They were used for climate forecasting, survey, natural resource management and space application.

Question 3: Which are the satellites that are used for telecommunication purposes?

Answer: Geo-stationary Satellites, also known as telecommunication satellites are used in satellite telephones, televisions, radios, etc. for communication across the globe.

Question 4: How was the INSAT series satellites launched into space?

Answer: The INSAT series satellites launched into space at the beginning of 1980 with the help of European launching vehicles. These satellites were used to collect telecommunication and weather data.

Question 5: Who was the first woman of Indian origin to have travelled in space?

Answer: Kalpana Chawla who was born on 17th March, 1962 was the first woman of Indian origin to have travelled in space. She died on 1st February, 2003 while returning to Earth in the Columbia space shuttle.

Question 6: Explain a few lines about Kalpana-1.

Answer: On 5th February, 2003 ISRO launched Kalpana-1 into space which was launched to obtain weather data. It was launched in memory of Kalpana Chawla, the first Indian woman into space. It is India’s first satellite that is related to weather science.

Question 7: What is the total number of artificial satellites that are being launched by different countries?

Answer: In the current generation, there are more than 3000 artificial satellites that were launched by different countries across the world.

Question 8: When was the first artificial satellite launched by India?

Answer: The first artificial satellite that was sent to space by India was in the year 1975. After that, more than 70 different varieties of satellites were launched in space by India.

Question 9: Which were the different countries that helped in launching Indian satellites?

Answer: Most of Indian satellites were launched into space through countries such as Russia, America, etc. through European satellite-launching vehicles, rockets and space shuttles.

Question 10: Which was India’s first experimental satellite in a remote sensing area?

Answer: Bhaskar-1 was sent into space in 1979 and it was India’s first experimental satellite in a remote sensing area.

Question 11: Write the names of 3 remote sensing satellites which were launched by India.

Answer: Three remote sensing satellites which were launched by India are listed as below:

(a) IRS – IA

(b) IRS-2B

(c) IRS-3C

Question 12: What is remote sensing?

Answer: Remote sensing is referred to as the process of getting information from an object without direct contact to the object.

Question 13: What are the uses of Polar Satellites?

Answer: Polar Satellites are used to send information of climate, geology, earth-water, etc as they pass through various positions at different time zones and locations in a particular day while revolving around the Earth,

Question 14: When was the first artificial satellite launched in space?

Answer: Russia was the first country in the world to launch the first artificial satellite into space on 4th October, 1957.

Question 15: Name the first educational satellite launched by India.

Answer: India launched the first educational satellite EDUSAT in the year 2004 which was meant for educational purposes.

Question 16: Name the first astronaut who travelled to space.

Answer: Yuri Gagarin of Russia was the first astronaut who travelled to space in 1961 in Vostok-I.

Answer: A geo-stationary satellite looks stationary from Earth because the amount taken by it to complete one cycle of the orbit is equal to the rotational period of the Earth, i.e, 24 hours.

Question 18: What is the minimum velocity for any object on Earth?

Answer: Escape velocity is the minimum velocity on Earth by which an object thrown upwards crosses the gravitational force of Earth. It is 11.2 km/sec for any object on Earth.

Question 19: What is the full form of ISRO and when was it re-established?

Answer: ISRO stands for Indian Space Research Organisation and it was re-established in the year 1969. It was previously known as Indian National Committee for Space Research (INCOSPAR).

Question 20: How is an artificial satellite launched into space?

Answer: Artificial satellites are usually sent into space through rockets and satellite launching vehicles.

Additional Long Type Answer Questions

Question 21: Explain an artificial satellite communication system with the help of a diagram.

Answer:

Satellite communication system

From the above diagram, we can analyse that an artificial satellite transmits radio signals or waves to the dish antenna, which are then converted into electromagnetic waves and signals. This helps in broadcasting the sound and image quality that we see and hear in various electronic gadgets such as television, mobiles, radios, etc.

When a person does some video recording that is being sent to the geo-station through electromagnetic signals, which are converted into radio waves and communicated to a telecommunication satellite. This is therefore an ongoing cycle where the data is converted into electromagnetic signals, which are read by our electronic gadgets and broadcasted through various channels such as radios, TVs or mobile phones, etc.

Question 22: Who was Dr. Vikram Ambalal Sarabhai? Write about him.

Answer: Dr. Vikram Ambalal Sarabhai was born on 12th August, 1919 in Ahmedabad, India. He was one of the most popular scientists in India who was honoured with ‘Padma Bhushan’ in the field of science and technology by the Government of India in the year 1966.

Dr. Sarabhai was the one who helped in recognition of India on the global platform. He received his Doctorate degree in “Cosmic Ray Physics” from Cambridge University located in the United Kingdom (U.K). He wrote 86 scientific research papers and established 40 institutions across various fields of science. One among them is Vikram Sarabhai Space Centre at Thiruvananthapuram and Space Application Centre located at Ahmedabad.

Dr. Vikram Ambalal Sarabhai was a visionary scientist and industrial manager having a rich interest in music, fine arts and photography. He passed away on 30th December, 1971 at the age of 52 years. He was honoured with ‘Padma Vibhushan’ posthumously.

Question 23: Write a brief summary about Dr. A.P.J. Abdul Kalam.

Answer: Dr. A.P.J. Abdul Kalam was born on 15th October, 1931. He was a scientist and engineer who was involved with major projects of Defence Research and Development Organization (DRDO) and Indian Space Research Organisation (ISRO).

During his tenure at ISRO, he played a vital role in designing and manufacturing India’s first indigenous satellite Satellite Launching Vehicle (S.L.V. – 3). In July 1980, the Rohini satellite was successfully launched with the help of this S.L.V. near the earth’s orbit. Later, India also became a member of the ‘International Space Club’.

Dr. Kalam had made a special contribution in the missile development program of India. He was also popularly known as “Missile Man” of India. Besides, he was the 11th President of India and contributed to the educational industry by writing various informative books.

The Government of India conferred him with the titles – ‘Padma Bhushan’ , ‘Padma Vibhushan’ ‘Bharat Ratna’ among other accolades for his contribution in the field of science and technology. He passed away on 27th July 2015 at Shillong, Meghalaya.

We hope that the above mentioned solutions of “RBSE Class 8 Science Chapter 12 Artificial Satellite” will help students build a strong foundation of the different concepts mentioned in the chapter.